[Bug 450699] New: lohit-fonts: Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug report.




https://bugzilla.redhat.com/show_bug.cgi?id=450699

           Summary: lohit-fonts: Errors in "sh" and "shrI" in Lohit
Tamil
                    font
           Product: Fedora
           Version: rawhide
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: low
          Priority: low
         Component: lohit-fonts
        AssignedTo: rbhalera(a)redhat.com
        ReportedBy: chandra(a)ee.uwa.edu.au
         QAContact: extras-qa(a)fedoraproject.org
                CC: chandra(a)ee.uwa.edu.au,fedora-fonts-bugs-
                    [e-mail],petersen(a)redhat.com


Description of problem: Errors in "sh" and "shrI" in Lohit Tamil font

Version-Release number of selected component (if applicable):

Kubuntu 8.04 (Hardy Heron)
ttf-indic-fonts-core version 1:0.5.0-0ubuntu1

Problems with "sh" and "shrI" in Lohit Tamil fonts:

A. The ITRANS Tamil character "sh" in Lohit Tamil is rendered as ஶ் : the dot
above or pulli should be over the character rather than beside it. Most other
consonants are rendered correctly. For example, the consonant "k" is correctly
rendered as க். I have been told that the "font must have a correct GPOS table
for pulli positioning and the rendering engine must utilise that information
when drawing the glyph" for the character to show up correctly. Of the two, I
think it more likely that it is the font rather than the rendering system that
is likely to be faulty because க் shows up correctly.

B. The character "shrI" should properly be rendered as ஸ்ரீ. This character
should
correctly be Unicode 0BB6 + 0BCD + 0BB0 + 0BC0 whereas in Lohit Tamil (and
possibly other Tamil fonts) it is made from Unicode 0BB8 + 0BCD + 0BB0 + 0BC0,
which is wrong. This should be corrected to accord with "The Unicode Standard,
Revision 5.0", p 325.

How reproducible:

Use SCIM or some scheme that allows raw Unicode to be input into a Unicode-aware
text editor and see the results onscreen.

Steps to Reproduce: A
1. Ensure that locale for Tamil is set up and that Lohit Tamil is default Tamil
font.
2. Install SCIM or other method to input raw Unicode from keyboard.
3. Into a Unicode-aware text editor, enter raw Unicode so: U+0BB6 + U+0BCD.
4. Verify that inputting U+0B95 + U+0BCD gives க் as expected. So problem lies
with font.
  
Actual results: For step 3: ஶ்

Expected results: For step 3: ஶ with dot (pulli) above as for க் above.

Steps to Reproduce: B
1. Ensure that locale for Tamil is set up and that Lohit Tamil is default Tamil
font.
2. Install SCIM or other scheme to input raw Unicode from keyboard.
3. Into a Unicode-aware text editor, enter raw Unicode so: 
U+0BB6 + U+0BCD + U+0BB0 + U+0BC0

Actual results: For step 3: ஶ்ரீ

Expected results: For step 3: ஸ்ரீ

Additional info:

1. The character ஸ்ரீ is wrongly encoded as U+0BB8 + U+0BCD + U+0BB0 + U+0BC0 in
Lohit Tamil.
2. These errors could exist in other Tamil fonts in addition to Lohit Tamil.

-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug 450699] lohit-fonts: Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.


https://bugzilla.redhat.com/show_bug.cgi?id=450699


John Poelstra <poelstra(a)redhat.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |poelstra(a)redhat.com




-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

[Bug 450699] lohit-fonts: Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.


https://bugzilla.redhat.com/show_bug.cgi?id=450699


Bug Zapper <fedora-triage-list(a)redhat.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|rawhide                     |10

Padmanabhan V. K. <bugzillas+padREMOVETHISdu(a)gmail.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bugzillas+padREMOVETHISdu@g
                   |                            |mail.com




--- Comment #1 from Bug Zapper <fedora-triage-list(a)redhat.com&gt;  2008-11-25 21:24:09
EDT ---

This bug appears to have been reported against 'rawhide' during the Fedora 10
development cycle.
Changing version to '10'.

More information and reason for this action is here:
http://fedoraproject.org/wiki/BugZappers/HouseKeeping

--- Comment #2 from Padmanabhan V. K. <bugzillas+padREMOVETHISdu(a)gmail.com&gt; 
2009-01-22 15:38:35 EDT ---
(In reply to comment #0)
>  A. The ITRANS Tamil character "sh" in Lohit Tamil is
> rendered as ஶ் : the dot
>  above or pulli should be over the character rather than beside it. Most other
>  consonants are rendered correctly. For example, the consonant "k" is correctly
>  rendered as க். I have been told that the "font must have a correct GPOS table
>  for pulli positioning and the rendering engine must utilise that information
>  when drawing the glyph" for the character to show up correctly. Of the two, I
>  think it more likely that it is the font rather than the rendering system that
>  is likely to be faulty because க் shows up correctly.
>   
IMHO the rendering engine is faulty. Since you use Kubuntu, I'd assume your
rendering engine is whatever QT/KDE uses (probably that's just called QT?).
Hence this part of the issue should be reported to them.

In my case I found the same issue with Lohit Tamil with the Pango rendering
engine (used in GTK+/GNOME/etc.). Downloading the source for my version of
Pango and changing one of its file worked for me.

The latest version of the pango file can be viewed here:
http://svn.gnome.org/viewvc/pango/trunk/modules/indic/indic-ot-class-tabl...
In the array tamlCharClasses[], entry 55 (corresponding to unicode character
0BB6) should be changed to _ct instead of _xx for "sh," "shaa,"
"shi," etc. to
be rendered properly.

If I can get over my laziness I'll probably file a bug for this on Pango.

>  B. The character "shrI" should properly be rendered as
> ஸ்ரீ. This character should
>  correctly be Unicode 0BB6 + 0BCD + 0BB0 + 0BC0 whereas in Lohit Tamil (and
>  possibly other Tamil fonts) it is made from Unicode 0BB8 + 0BCD + 0BB0 + 0BC0,
>  which is wrong. This should be corrected to accord with "The Unicode Standard,
>  Revision 5.0", p 325. 
I agree that Lohit Tamil should be enhanced to render 0BB6 + 0BCD + 0BB0 + 0BC0
also as the "shri" ligature. However for backward-compatibility 0BB8 + 0BCD +
0BB0 + 0BC0 should probably also produce the "shri" ligature -- there would
certainly be older documents where this encoding was used for the "shri"
ligature, and other fonts also seem to have used this encoding, e.g. all the
fonts in Mandriva's fonts-ttf-tamil-1.1-2mdk package that are installed in the
machine I am typing this from.

But Lohit Tamil is producing the ligature for 0BB7 + 0BCD + 0BB0 + 0BC0, which
doesn't seem to be useful.

HTH, Thanks!

-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

[Bug 450699] lohit-fonts: Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.


https://bugzilla.redhat.com/show_bug.cgi?id=450699





--- Comment #3 from Padmanabhan V. K. <bugzillas+padREMOVETHISdu(a)gmail.com&gt; 
2009-01-23 12:42:27 EDT ---
(In reply to comment #2)
>  In my case I found the same issue with Lohit Tamil with the Pango
> rendering
>  engine (used in GTK+/GNOME/etc.). Downloading the source for my version of
>  Pango and changing one of its file worked for me.
>  
>  The latest version of the pango file can be viewed here:
>
> http://svn.gnome.org/viewvc/pango/trunk/modules/indic/indic-ot-class-tabl...
>  In the array tamlCharClasses[], entry 55 (corresponding to unicode character
>  0BB6) should be changed to _ct instead of _xx for "sh," "shaa,"
> "shi," etc. to
>  be rendered properly.
>  
>  If I can get over my laziness I'll probably file a bug for this on Pango. 
I found that there is already a bug for this in Pango:
http://bugzilla.gnome.org/show_bug.cgi?id=481203
This was also tracked here in bug 218905 which has since been closed for being
filed against an old rawhide version.
http://bugzilla.gnome.org/attachment.cgi?id=127113 shows the rendering with the
fix in Pango (with no fix required in Lohit Tamil for this particular issue).

-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

[Bug 450699] lohit-fonts: Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.


https://bugzilla.redhat.com/show_bug.cgi?id=450699





--- Comment #4 from Rahul Bhalerao <rbhalera(a)redhat.com&gt;  2009-03-04 09:11:58 EDT
---
I am patching the font file for proper combination with 0bb6, but it wont work
unless the corresponding patch for pango is commited.

-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

[Bug 450699] [ta_IN] Errors in "sh" and "shrI" in Lohit Tamil font

[Red Hat Bugzilla]

Please do not reply directly to this email. All additional
comments should be made in the comments box of this bug.


https://bugzilla.redhat.com/show_bug.cgi?id=450699


Rahul Bhalerao <rbhalera(a)redhat.com&gt; changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |CLOSED
         Resolution|                            |RAWHIDE
            Summary|lohit-fonts: Errors in "sh" |[ta_IN] Errors in
"sh" and
                   |and "shrI" in Lohit Tamil   |"shrI" in Lohit Tamil
font
                   |font                        |




--- Comment #5 from Rahul Bhalerao <rbhalera(a)redhat.com&gt;  2009-03-05 09:24:55 EDT
---
Font fixed in lohit-fonts-2.3.8. Please wait for an update in pango for final
resolve.

-- 
Configure bugmail: https://bugzilla.redhat.com/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.